Combining rotating and gyrating structures, to achieve a specific velocity of a mass, within a device, can reduce the number of parts as compared to a design using only gyration induced acceleration, and can reduce the absolute dimensions compared to a design using only rotation induced acceleration. Synchronous motions allow the accelerated mass to transition from a rotating reference frame to a gyrating reference frame without a significant physical gap or jump, greatly reducing any potential for ricochet. Re-phasing within the device may be accomplished several times. The mass is ejected and directed toward a target.